High Cycle Fatigue Performance of LPBF 304L Stainless Steel at Nominal and Optimized Parameters

In additive manufacturing, the variation of the fabrication process parameters influences the mechanical properties of a material such as tensile strength, impact toughness, hardness, fatigue strength, and so forth, but fatigue testing of metals fabricated with all different sets of process paramete...

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Bibliographic Details
Main Authors: Mohammad Masud Parvez, Tan Pan, Yitao Chen, Sreekar Karnati, Joseph W. Newkirk, Frank Liou
Format: Article
Language:English
Published: MDPI AG 2020-03-01
Series:Materials
Subjects:
Online Access:https://www.mdpi.com/1996-1944/13/7/1591
Description
Summary:In additive manufacturing, the variation of the fabrication process parameters influences the mechanical properties of a material such as tensile strength, impact toughness, hardness, fatigue strength, and so forth, but fatigue testing of metals fabricated with all different sets of process parameters is a very expensive and time-consuming process. Therefore, the nominal process parameters by means of minimum energy input were first identified for a dense part and then the optimized process parameters were determined based on the tensile and impact toughness test results obtained for 304L stainless steel deposited in laser powder bed fusion (LPBF) process. Later, the high cycle fatigue performance was investigated for the material built with these two sets of parameters at horizontal, vertical, and inclined orientation. In this paper, displacement controlled fully reversed (R = −1) bending type fatigue tests at different levels of displacement amplitude were performed on Krouse type miniature specimens. The test results were compared and analyzed by applying the control signal monitoring (CSM) method. The analysis shows that specimen built-in horizontal direction for optimized parameters demonstrates the highest fatigue strength while the vertical specimen built with nominal parameters exhibits the lowest strength.
ISSN:1996-1944